Multilevel vulcanizing presses such as a two-level vulcanizing press are known in the art. These presses generally include a press housing and two servicing stations disposed on both sides of the press housing to accommodate molding tools which can be opened at right angles to the mold parting plane. Each molding tool can include a plurality of mold plates and is movable via guide means from the press housing into one of the servicing stations and vice versa. Each molding tool can be opened and closed within the press housing.
In order to produce particularly small mass-produced articles of rubber, such as gaskets, for example, molding tools are used which, depending on their structural configuration and size of the articles to be produced therewith, comprise three or more mold plates which usually have multinested inserts. Particularly, when injection molding processes are employed, further mold plates are required to hold the injection cylinder and piston.
Depending on the size of the molding tool and the required pressure, it is possible to simultaneously accommodate in one vulcanizing press a plurality of molding tools which are arranged at different levels. The dual-level presses often used for this purpose include a columnar press housing and two servicing stations disposed opposite one another at both sides of the press housing. While the press serves to close, vulcanize and open the molding tools, the servicing stations are provided for emptying, cleaning and possibily filling the individual mold plates.
For this purpose, the mold plates of each molding tool are individually moved via guide rails from the press into their respective servicing stations where both sides of each plate are made accessible to the operating personnel by pivoting each plate 180.degree. about a horizontal axis.
In the past only one mold plate could be serviced at a time and the press was therefore maintained in an open position until the servicing of all plates was completed. Keeping the press open during this servicing period causes the temperature in the press to drop considerably so that much time and energy had to be expended before each new vulcanization process. In addition, the capacity of the press was utilized only about one-half, if it is assumed that the servicing period, as a rough estimate, approximately corresponds to the pressing period.
German Pat. No. 1,032,568 discloses a phonograph record press with two pressing levels where during servicing of one molding tool a second molding tool is in the press at the same level. By alternatingly removing the one molding tool from the press and simultaneously introducing the other molding tool into the press the servicing of the molding tools can take place parallel in time with the pressing process so that a shorter operating cycle is attained for the press. In the known phonograph record press this can very easily be structurally realized since the molding tools consist merely of two molding plates which can be opened in the manner of a hinge for producing a single easily removable article.